#ifndef NOTES_H
#define NOTES_H
+/*
+ * Function type for combining two notes annotating the same object.
+ *
+ * When adding a new note annotating the same object as an existing note, it is
+ * up to the caller to decide how to combine the two notes. The decision is
+ * made by passing in a function of the following form. The function accepts
+ * two SHA1s -- of the existing note and the new note, respectively. The
+ * function then combines the notes in whatever way it sees fit, and writes the
+ * resulting SHA1 into the first SHA1 argument (cur_sha1). A non-zero return
+ * value indicates failure.
+ *
+ * The two given SHA1s must both be non-NULL and different from each other.
+ *
+ * The default combine_notes function (you get this when passing NULL) is
+ * combine_notes_concatenate(), which appends the contents of the new note to
+ * the contents of the existing note.
+ */
+typedef int combine_notes_fn(unsigned char *cur_sha1, const unsigned char *new_sha1);
+
+/* Common notes combinators */
+int combine_notes_concatenate(unsigned char *cur_sha1, const unsigned char *new_sha1);
+int combine_notes_overwrite(unsigned char *cur_sha1, const unsigned char *new_sha1);
+int combine_notes_ignore(unsigned char *cur_sha1, const unsigned char *new_sha1);
+
/*
* Notes tree object
*
*/
extern struct notes_tree {
struct int_node *root;
+ struct non_note *first_non_note, *prev_non_note;
char *ref;
+ combine_notes_fn *combine_notes;
int initialized;
} default_notes_tree;
*
* If you pass t == NULL, the default internal notes_tree will be initialized.
*
+ * The combine_notes function that is passed becomes the default combine_notes
+ * function for the given notes_tree. If NULL is passed, the default
+ * combine_notes function is combine_notes_concatenate().
+ *
* Precondition: The notes_tree structure is zeroed (this can be achieved with
* memset(t, 0, sizeof(struct notes_tree)))
*/
-void init_notes(struct notes_tree *t, const char *notes_ref, int flags);
+void init_notes(struct notes_tree *t, const char *notes_ref,
+ combine_notes_fn combine_notes, int flags);
/*
* Add the given note object to the given notes_tree structure
* zero.
*/
void add_note(struct notes_tree *t, const unsigned char *object_sha1,
- const unsigned char *note_sha1);
+ const unsigned char *note_sha1, combine_notes_fn combine_notes);
/*
* Remove the given note object from the given notes_tree structure